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    Ch.4 Respiration

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    piggypeggy31032020

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    Ch.4 Respiration

    Uploaded by

    piggypeggy31032020
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    3 views2 pages

    Ch.4 Respiration

    Uploaded by

    piggypeggy31032020

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
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    Chapter 4 : Respiration

    I. What is respiration?
    1. Respiration releases energy
    - You should remember that the blood carries dissolved food, mostly in the form of glucose, and oxygen to the cells of
    the body. You should also remember that food contains stored energy.
    - Our cells use the energy they get from food as a a fuel to carry out all our life processes.
    - But the stored energy in food needs to be release so that it can be used by the body.
    - When our cells release energy from food, we call it cellular respiration.
    - Respiration takes place in all the
    living cells in the body.
    - It is a chemical reaction in which
    oxygen combines with food (glucose) in
    the cell to release energy.
    - Carbon dioxide and water are the
    waste products of respiration.
    - Some of the water is used by the
    cells, but the rest of the water and the
    carbon dioxide pass from the cells back
    into the blood to be exhaled.
    - The picture beside shows what
    happen:

    - Word equation of the process of respiration:

    -Chemical equation of the process of respiration:

    - The chemical changes that happen in respiration explain why the air we inhale is different from the air we exhale.
    - Since this type of respiration uses oxygen, we call it aerobic respiration.
    - The word “aero” comes from Greek word for air.

    2. Using the energy from respiration


    - The picture below shows how the energy produced by respiration is used. Eventually, we lose most of the energy we
    produce in the form of heat.

    II. Respiration without oxygen


    - Aerobic respiration is able to provide our body with the energy we need for normal activities.
    - If we exercise or play sport, we need more energy.
    - To supply this energy, aerobic respiration has to take place at a faster rate. This means that our cells need more food
    and oxygen than they normally have, and they have to get rid of more carbon dioxide and water than they usually do.
    - Three things happen when we exercise to make it possible for our cells to respire faster and our blood to get rid of the
    waste products of respiration:
    + Our breathing rate increases: this means that gas exchange in the lungs take place faster, so more oxygen can get
    into the blood and more carbon dioxide can be exhaled.
    + Our heart rate increases: this means that blood is pumped round the body at a faster rate.
    + More blood flows to the muscles: this provides them with a bigger supply of dissolve food and oxygen.

    1. What happens if there is not enough oxygen?


    - Your breathing rate and heart rate cannot increase endlessly and sometime when you exercise really hard, your
    muscles might not get enough oxygen.
    - When this happens, the muscles can respire for a short time without oxygen. This process is called anaerobic
    respiration.
    - During anaerobic respiration, glucose is changed to lactic acid and a small amount of energy is released.
    - Word equation for anaerobic respiration:

    - Lactic acid is poisonous. It makes your muscles tired and sore, and it can give you a stitch or a cramp in a muscle.

    2. Oxygen debt
    - Lactic acid builds up in the muscles during anaerobic respiration.
    - It has to be broken down and removed from the body.
    - This happens when the lactic acid combines with oxygen to form carbon dioxide and water.
    - You breathe heavily for a time after you stop exercising to take in the extra oxygen your body needs to break down
    and remove the lactic acid.
    - The amount of oxygen needed to break down the lactic acid is called the oxygen debt.
    - The more oxygen you need, the bigger your oxygen debt and the longer you will breathe heavily after stopping
    exercise.
    - Your breathing and heart rate will only go back to normal once you have repaid the oxygen debt.

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